Medium transporting device and medium processing apparatus using medium transporting device

ABSTRACT

A medium transporting device includes a positioning and transporting section that transports a medium after positioning a leading end position of the medium, an upstream transporting section that is provided on an upstream side of the positioning and transporting section in a medium transport direction and transports the medium toward the positioning and transporting section, plural detection sections that are provided on a downstream side of the positioning and transporting section in the medium transport direction and detect, at plural places of a reference line intersecting the transport direction of the medium, a timing at which a leading end or a trailing end of the medium passing through the positioning and transporting section passes, and a determination section that determines presence or absence of a wrinkle of the medium using detection results of the plural detection sections.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2022-052968 filed Mar. 29, 2022.

BACKGROUND (i) Technical Field

The present invention relates to a medium transporting device and a medium processing apparatus using the medium transporting device.

(ii) Related Art

In the related art, as a medium transporting device of this type, for example, a device described in JP1993-24716A is already known.

JP1993-24716A discloses a medium control method of a medium separation feeding device that detects a front surface state of a medium, such as a fed medium with a wrinkle or no wrinkle, combines detection information of a traveling state of the medium with detection information of the front surface state of the medium in a case of medium feeding state control, and in a case of adjusting a meshing amount between a feeding roller and a separating roller on the right and the left according to the traveling state of the medium, adjusts the meshing amount to a different amount according to the front surface state of the medium.

SUMMARY

Aspects of non-limiting embodiments of the present disclosure relate to a medium transporting device and a medium processing apparatus using the medium transporting device that determine the presence or absence of a wrinkle of a medium with a simple configuration in accordance with positioning of a leading end position of the medium.

Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above.

According to an aspect of the present disclosure, there is provided a medium transporting device including a positioning and transporting section that transports a medium after positioning a leading end position of the medium, an upstream transporting section that is provided on an upstream side of the positioning and transporting section in a medium transport direction and transports the medium toward the positioning and transporting section, a plurality of detection sections that are provided on a downstream side of the positioning and transporting section in the medium transport direction and detect, at a plurality of places of a reference line intersecting the transport direction of the medium, a timing at which a leading end or a trailing end of the medium passing through the positioning and transporting section passes, and a determination section that determines presence or absence of a wrinkle of the medium using detection results of the plurality of detection sections.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiment(s) of the present invention will be described in detail based on the following figures, wherein:

FIG. 1A is an explanatory diagram showing an outline of an exemplary embodiment of a medium processing apparatus into which a medium transporting device, to which the present invention is applied, is incorporated, FIG. 1B is an explanatory diagram showing a configuration example of a plurality of detection sections in a case where the medium transporting device shown in FIG. 1A is viewed from a B-direction, and FIG. 1C is an explanatory diagram showing another configuration example of the plurality of detection sections;

FIG. 2 is an explanatory diagram showing an overall configuration of an image forming apparatus, which is a medium processing apparatus according to exemplary embodiment 1;

FIG. 3 is an explanatory diagram showing major portions of the medium transporting device used in the image forming apparatus according to exemplary embodiment 1;

FIG. 4A shows a configuration example of a position sensor used in the medium transporting device according to exemplary embodiment 1, and FIG. 4B is an explanatory diagram showing a configuration example of a position sensor used in a medium transporting device according to exemplary embodiment 2;

FIG. 5 is a flowchart showing paper wrinkle determination processing of the medium transporting device according to exemplary embodiment 1;

FIG. 6A is an explanatory diagram showing a relative positional relationship between paper and two position sensors during normal transport, FIG. 6B is an explanatory diagram showing a relative positional relationship between the paper and the two position sensors during oblique transport, and FIG. 6C is an explanatory diagram showing a relative positional relationship between the paper with a paper wrinkle and the two position sensors;

FIG. 7A is an explanatory diagram showing an output example of the two position sensors with respect to the paper (FIG. 6A) during normal transport, FIG. 7B is an explanatory diagram showing an output example of the two position sensors with respect to the paper (FIG. 6B) during oblique transport, and FIG. 7C is an explanatory diagram showing an output example of the two position sensors with respect to the paper (FIG. 6C) with the paper wrinkle;

FIG. 8 is a flowchart showing paper wrinkle determination processing of the medium transporting device according to exemplary embodiment 2;

FIG. 9A is an explanatory diagram showing a relative positional relationship between the paper and three position sensors during normal transport, FIG. 9B is an explanatory diagram showing a relative positional relationship between the paper and the three position sensors during oblique transport, and FIG. 9C is an explanatory diagram showing a relative positional relationship between the paper with the paper wrinkle and the three position sensors;

FIG. 10A is an explanatory diagram showing a pattern example of a paper wrinkle that can be determined in any of exemplary embodiments 1 and 2, and FIG. 10B is an explanatory diagram showing a pattern example of a paper wrinkle that is difficult to be determined in exemplary embodiment 1 but can be determined in exemplary embodiment 2; and

FIG. 11A is an explanatory diagram showing an output example of the three position sensors with respect to the paper (FIG. 9A) during normal transport, FIG. 11B is an explanatory diagram showing an output example of the three position sensors with respect to the paper (FIG. 9B) during oblique transport, FIG. 11C is an explanatory diagram showing an output example of the three position sensors with respect to the paper (FIG. 9C) with the paper wrinkle, and FIG. 11D is an explanatory diagram showing an output example of the three position sensors with respect to the paper (FIG. 10A) with the paper wrinkle.

DETAILED DESCRIPTION Outline of Exemplary Embodiment

FIG. 1A is an explanatory diagram showing an outline of an exemplary embodiment of a medium processing apparatus into which a medium transporting device, to which the present invention is applied, is incorporated.

In FIG. 1A, the medium processing apparatus includes a medium transporting device 10 that transports a medium S and a processing section 11 that performs processing determined in advance on the medium S transported by the medium transporting device 10.

In the present example, a representative aspect of the medium transporting device 10 includes a positioning and transporting section 1 that transports the medium S after positioning a leading end position of the medium S, an upstream transporting section 2 that is provided on an upstream side of the positioning and transporting section 1 in a medium transport direction and transports the medium S toward the positioning and transporting section 1, a plurality of detection sections 3 that are provided on a downstream side of the positioning and transporting section 1 in the medium transport direction and detect a timing at which a leading end or a trailing end of the medium S passing through the positioning and transporting section 1 passes at a plurality of places of a reference line L intersecting a transport direction of the medium S, and a determination section 4 that determines the presence or absence of a wrinkle of the medium S using detection results of the plurality of detection sections 3.

In addition, another representative aspect of the medium transporting device 10 includes the positioning and transporting section 1 that transports the medium S after positioning the leading end position of the medium S, the upstream transporting section 2 that is provided on the upstream side of the positioning and transporting section 1 in the medium transport direction and transports the medium S toward the positioning and transporting section 1, the plurality of detection sections 3 that are provided on the downstream side of the positioning and transporting section 1 in the medium transport direction and detect a timing at which the leading end or the trailing end of the medium S passing through the positioning and transporting section passes at a plurality of places of the reference line L intersecting the transport direction of the medium S, and the determination section 4 that determines an oblique state of the leading end in the transport direction of the medium S and the presence or absence of a wrinkle of the medium using detection results of the plurality of detection sections 3.

That is, the former representative aspect is an aspect in which the presence or absence of a wrinkle of the medium S is determined using the plurality of detection sections 3, and the latter representative aspect is an aspect in which the oblique state of the medium S and the presence or absence of the wrinkle of the medium are determined using the plurality of detection sections 3.

In such technical means, since positioning rollers configured as a pair are stopped and the leading end of the medium S is blocked in a positioning system of the positioning and transporting section 1, a known method including a method of aligning the leading end position of the medium S along the positioning rollers by releasing a nipped state (nip) of the medium S caused by the upstream transporting section 2 may be selected as appropriate.

In addition, as the plurality of detection sections 3, a mechanical type including an optical type may be selected as appropriate insofar as timings at which the leading end and the trailing end of the medium S pass can be detected. In addition, as shown in FIGS. 1B and 1C, the plurality of detection sections 3 may be provided to correspond to the plurality of places of the reference line L and do not include a line sensor that can continuously perform detection.

Further, the determination section 4 widely includes a determination section adopting a method of determining the oblique state (skew) of the medium S and the presence or absence of a wrinkle.

Next, a representative aspect or an appropriate aspect of configuration requirements of the medium transporting device 10 will be described in the present exemplary embodiment.

First, as a representative aspect of the plurality of detection sections 3, there are sections sharing a detection section that detects the oblique state of the leading end in the transport direction of the medium S. In the present example, in the medium transporting device 10 on which the detection section detecting the oblique state of the leading end in the transport direction of the medium S is already mounted, it is not necessary to use a dedicated detection section for determining the presence or absence of a paper wrinkle of the medium S, and by the amount, it is possible to reduce costs of the plurality of detection sections 3.

In addition, from a perspective of learning the oblique state of the medium S and the presence or absence of a wrinkle of the medium S early, for example, it is preferable to provide the plurality of detection sections 3 immediately behind the positioning and transporting section 1. In the present example, from a perspective of detecting position information of the leading end or the trailing end in the transport direction of the medium S in a wide range, for example, an aspect in which all or some of the plurality of detection sections 3 are divided and arranged close to both end portions in a width direction intersecting the transport direction of the medium S is preferable.

In addition, as an appropriate aspect of the plurality of detection sections 3, as shown in FIG. 1B, the plurality of detection sections 3 means two (specifically, 3 a and 3 b), and the detection sections detect timings at which the leading end and the trailing end in the transport direction of the medium S pass. In this case, the determination section 4 may determine whether there is a wrinkle in the medium S on a condition in which inclination amount differences of the leading end and the trailing end in the transport direction of the medium S with respect to the reference line L are larger than a threshold determined in advance.

Further, as another appropriate aspect of the plurality of detection sections 3, as shown in FIG. 1C, the plurality of detection sections 3 means three or more (for example, 3 a to 3 c), and the detection sections that detect timings at which the leading end and the trailing end in the transport direction of the medium S pass. In this case, the determination section 4 may determine whether there is a wrinkle in the medium S on a condition in which inclination amounts of the leading end and the trailing end in the transport direction of the medium S with respect to the reference line L are not uniform in the width direction of the medium S.

In addition, as an appropriate aspect of the determination section 4, there is an aspect in which it is determined that a transport posture of the medium S is excessively oblique on a condition in which the oblique state of the leading end in the transport direction of the medium S exceeds a threshold determined in advance and the presence or absence of a wrinkle in the medium S is determined under a condition in which the oblique state is equal to or smaller than the threshold. In this case, although the presence or absence of a wrinkle is determined with respect to all of the media S, considering the fact that a wrinkle is likely to be generated in a case where the medium S is a medium having a thickness that is equal to or smaller than a thickness determined in advance, the presence or absence of a wrinkle in the medium S may be determined in a case where the medium S is a medium having a thickness that is equal to or smaller than the thickness determined in advance.

Further, a removal processing section 6 that performs, in a case where the determination section 4 determines that there is a wrinkle in the medium S, removal processing for removing the medium S with the wrinkle from a transport path may be included. Herein, the removal processing section 6 adopts a method in which the medium S is stopped being transported and a user performs removal in a transport stopping mode and a method in which another discharging and accommodating means discharges the medium in a transport continuation mode. Further, a notification section 7 that issues, in a case where the determination section 4 determines that there is a wrinkle in the medium S, a notification of the presence of the wrinkle in the medium S may be included.

Hereinafter, the present invention will be further described in detail based on the exemplary embodiment shown in the accompanying drawings.

Exemplary Embodiment 1

FIG. 2 is an explanatory diagram showing an overall configuration of an image forming apparatus, which is the medium processing apparatus according to exemplary embodiment 1.

Overall Configuration of Image Forming Apparatus

In FIG. 2 , in a basic configuration of the image forming apparatus, for example, an image forming engine 21 for forming a plurality of color component images is mounted in a device housing 20, and below the image forming engine 21, a medium transport system 80 that transports a medium to the image forming engine 21 and a fixing device 70 that fixes an image formed by the image forming engine 21 to a medium are included.

In the present example, the image forming engine 21 includes image forming units 22 (specifically, 22 a to 22 d) that form images having general colors of a plurality of color components (yellow (Y), magenta (M), cyan C, and black (K) in the present exemplary embodiment), a belt-shaped intermediate transfer body 30 that transfers (primarily transfers) each color component image formed by each image forming unit 22 in turn, and a secondary transfer device (collective transfer device) 50 that secondarily transfers (collectively transfers) each color component image transferred on the intermediate transfer body 30 to a medium (paper or a film). In FIG. 2 , the reference sign 40 is an operation panel for operating the image forming apparatus.

Image Forming Unit

In the present exemplary embodiment, each of the image forming units 22 (22 a to 22 d) has each drum-shaped photoreceptor 23, and around each photoreceptor 23, a charging device 24 that charges the photoreceptor 23, such as a corotron and a transfer roller, an exposure device 25 that writes an electrostatic latent image on the charged photoreceptor 23, such as a laser scanning device, a developing device 26 that develops the electrostatic latent image written on the photoreceptor 23 with each of YMCK color component toners, a primary transfer device 27 that transfers a toner image on the photoreceptor 23 to the intermediate transfer body 30, such as a transfer roller, and a photoreceptor cleaning device 28 that removes a residual toner on the photoreceptor 23 are respectively arranged.

In addition, the intermediate transfer body 30 is hung on a plurality of (three, in the present exemplary embodiment) tension rollers 31 to 33. For example, the tension roller 31 is used as a drive roller driven by a drive motor (not shown) and is circulated and moved by the drive roller. Further, an intermediate transfer body cleaning device 35 for removing a residual toner on the intermediate transfer body 30 after secondary transfer is provided between the tension rollers 31 and 33.

Secondary Transfer Device (Collective Transfer Device)

Further, in the secondary transfer device (collective transfer device) 50, for example, a transfer roller 55 is pressure-welded and arranged at a part facing the tension roller 33 of the intermediate transfer body 30, and the tension roller 33 of the intermediate transfer body 30 is formed as a facing roller 56 of a facing electrode, which is the transfer roller 55. Herein, in the present example, the transfer roller 55 has a configuration where an elastic layer, in which carbon black is mixed with urethane foam rubber and EPDM, is coated around a metal shaft. A transfer voltage from a transfer power supply (not shown) is applied to the facing roller 56 (also serving as the tension roller 33 in the present example) via a conductive power supply roller (not shown). On the other hand, a predetermined transfer electric field is formed between the transfer roller 55 and the facing roller 56 by grounding the transfer roller 55, and a nipping region of the intermediate transfer body 30 nipped between the transfer roller 55 and the facing roller 56 functions as a secondary transfer region (collective transfer region) TR. Although the secondary transfer device 50 has an aspect in which the transfer roller 55 is used, the secondary transfer device is not limited thereto. It is evident that a transfer belt module on which a transfer belt is hung may be used as the transfer roller 55, which is one tension roller.

Fixing Device

The fixing device 70 is a device that has a heating and fixing roller 71 which is driven to be rotatable and is arranged to be in contact with an image holding surface side of a medium and a pressurizing and fixing roller 72 which is pressure-welded and arranged to face the heating and fixing roller 71 and rotates to follow the heating and fixing roller 71, that causes an image held on the medium in a fixing region between both fixing rollers 71 and 72 to pass, and that heats, pressurizes, and fixes the image.

Herein, a heater is mounted in, for example, a roller body of the heating and fixing roller 71, or the roller body is heated by bringing an external heater into contact with a roller body outer peripheral surface. In addition, it is evident that the heater may be added to the pressurizing and fixing roller 72 as necessary. The present example shows an example of rollers configured as a pair, but the present invention is not limited thereto. The heating and fixing roller 71 may be selected as appropriate, for example, by configuring a heating and fixing belt in which an electromagnetic induction heating method is adopted.

Medium Transport System

Further, the medium transport system 80 has a plurality of stages (two stages in the present example) of medium supply containers 81 and 82. A medium supplied from any one of the medium supply containers 81 and 82 reaches the secondary transfer region TR from a vertical transport path 83 extending in a substantially vertical direction via a horizontal transport path 84 extending in a substantially horizontal direction. After then, the medium holding the transferred image reaches a fixing part generated by the fixing device 70 via a transport belt 85 and is discharged to a medium discharge receiver 86 provided on the side of the device housing 20.

Further, the medium transport system 80 has, in the horizontal transport path 84, a reversible branched transport path 87 that branches from a portion positioned on the downstream side of the fixing device 70 in the medium transport direction. The medium reversed at the branched transport path 87 returns and returns again from the vertical transport path 83 to the horizontal transport path 84 via a transport path 88. An image is transferred to the back surface of the medium in the secondary transfer region TR, and the medium is discharged to the medium discharge receiver 86 via the fixing device 70. The branched transport path 87 is provided with a branch return transport path 89, which is branched from the middle and through which a reversed medium is transported to a medium discharge receiver 86 side.

In addition, the medium transport system 80 is provided with an appropriate number of transport rollers 91 in the transport paths 83, 84, 87, 88, and 89 respectively, in addition to a position aligning roller 90, which is positioning and transporting means for aligning the position of the medium and supplying the medium to the secondary transfer region TR. In addition, a manual feeding medium supplier 92 that is capable of supplying a manually fed medium toward the horizontal transport path 84 is provided on an opposite side of the medium discharge receiver 86 of the device housing 20.

Necessity of Determining Presence or Absence of Paper Wrinkle

In this type of image forming apparatus, there is a demand for widely using paper (from thick paper to thin paper) having thicknesses different from each other as a medium. In such a demand, in a case of using, for example, thin paper of 80 gsm or lower, in particular, thin paper 60 gsm or lower, a paper wrinkle may be generated.

For a defect such as a paper wrinkle of this type, in the past, for example, a system in which an image line sensor (ILS) is arranged in a transport path of a medium and a paper wrinkle in the passing medium is inspected, or in which an automatic inspection device is introduced and inspects the presence or absence of a paper wrinkle with respect to an output material discharged to a medium discharge receiver is already provided.

However, as for providing the ILS, it is necessary to select a horizontal transport path in order to improve inspection accuracy. There are restrictions in a place to be set, the size of the ILS is large as well, and costs are high. In addition, since the automatic inspection device is a system that inspects the output material of the medium, the automatic inspection device is retrofitted to the image forming apparatus. Thus, a provision space increases, the size is large as well, and costs are high.

In the present exemplary embodiment, it is considered to adopt an inexpensive system that determines the presence or absence of a paper wrinkle by effectively using a configuration example of the existing medium transporting device.

Basic Configuration of Medium Transporting Device

In the present exemplary embodiment, as shown in FIGS. 2 and 3 , the medium transporting device 100 has a basic configuration where the leading end position of the medium S is aligned and the medium reaches the secondary transfer region TR in a state where the transport posture of the medium S is not oblique, in transporting the medium S to the secondary transfer region TR.

In the present example, the medium transporting device 100 of this type includes the position aligning roller 90 that is the positioning and transporting section which aligns the leading end position of the medium S, a transport roller 91 f (91) that is the upstream transporting section arranged on the upstream side of the position aligning roller 90 in the transport direction of the medium S, and two position sensors 110 (specifically 111 and 112) that are a plurality of detection sections which are on the downstream side of the position aligning roller 90 in the transport direction of the medium S and which are for detecting whether or not the leading end of the medium S, which has passed through the position aligning roller 90, is in the oblique state.

Position Aligning Roller

The position aligning roller 90 includes a drive roller 121 that corresponds to a so-called registration roller and has a roller body around a rotation shaft and a driven roller 122 that is driven to rotate while being in contact with the drive roller 121 and has a roller body around a rotation shaft. A drive motor 123 is drivingly connected to the drive roller 121 via a drive transmission component (not shown). In addition, the driven roller 122 is supported by a nipping releasing mechanism 124, moves to be capable of coming into contact with and separating away from (nipping releasing) the drive roller 121, forms a contact region (nipping region) where the medium S is nipped between the drive roller 121 and the driven roller, and moves to a retracted position separated away from the contact region. In a case where the position aligning roller 90 positions the leading end of the medium S, a nipping state of the driven roller 122 with respect to the drive roller 121 is maintained, and the drive motor 123 temporarily stops driving the drive roller 121.

Transport Roller

Like the position aligning roller 90, the transport roller 91 f includes a drive roller 131 and a driven roller 132, the drive roller 131 is drivingly connected to a drive motor 133 via a drive transmission component (not shown), and the driven roller 132 is supported by a nipping releasing mechanism 134.

Position Sensor

In the present example, as shown in FIGS. 3 and 4A, the position sensors 110 (111 and 112) are provided at a plurality of places (two places in the present example) of the reference line L along the width direction intersecting the transport direction of the medium S, immediately behind the position aligning roller 90 (parts separated away from the position aligning roller 90 by m, in the present example). The position sensors 110 (111 and 112) of the present example are divided and arranged close to both end portions in the width direction intersecting the transport direction of the medium S and can detect a timing at which the leading end or the trailing end of the medium S passing through the position aligning roller 90 passes as a width dimension w between the two including the position sensors 111 and 112 is set to be shorter than a width dimension of the medium S having a usable size.

Herein, as the position sensors 110 (111 and 112), optical sensors each of which has a light emitting unit and a light receiving unit and in which a boundary portion between a region from the leading end to the trailing end in the transport direction of the medium S and the other region appears as an output change of the light receiving unit by detecting reflected light from the light emitting unit with the light receiving unit in a case where the medium S passes are adopted. It is also possible to use a mechanical sensor and an electric sensor, other than an optical sensor, as the position sensor 110 insofar as positions of the leading end and the trailing end in the transport direction of the medium S can be learned.

Control System of Medium Transporting Device

In the present example, as shown in FIG. 3 , a control device 150 for determining the presence or absence of a paper wrinkle of the medium S is provided.

The control device 150 is configured by a microcomputer including various types of processors. Herein, the “processor” refers to a processor in a broad sense and includes a general-purpose processor (for example, a central processing unit (CPU)) and a dedicated processor (for example, a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and a programmable logic device).

In the present example, the control device 150 is a device that installs necessary programs such as a medium S position aligning operation program and a “program for determining the presence or absence of a paper wrinkle (see FIG. 5 )” in advance in a memory (not shown), takes, into the processor, detection information from the position sensors 110 (111 and 112) in a case where the medium S, which has passed through the position aligning roller 90, passes through the position sensors 110 (111 and 112) after performing a medium S position aligning operation (corresponding to an aligning (registration) operation by the position aligning roller 90), executes the “program for determining the presence or absence of a paper wrinkle”, and determines the presence or absence of a paper wrinkle of the medium S.

Medium Position Aligning Operation

As shown in FIG. 5 , the medium S position aligning operation by the position aligning roller (registration roller) 90 is performed before determining the presence or absence of a paper wrinkle of the medium S. In this operation, the driving of the position aligning roller 90 is stopped in the nipping state, the transport roller 91 f transports the medium S so that the leading end of the medium S is abutted against the position aligning roller 90, and skew correction is performed on the leading end of the medium S along an axial direction of the position aligning roller 90.

Medium Transport Resuming Operation

In a case where the medium S position aligning operation described above is completed, a transport operation of the medium S of which a position is aligned is resumed by the position aligning roller 90.

Then, in a case where the leading end of the medium S passes through the reference line L, the leading end passes through the position sensors 110 (111 and 112).

Herein, since the position sensors 110 (111 and 112) detect a skew of the leading end of the medium S, whether or not a leading end skewing amount is equal to or smaller than a threshold T0 determined in advance is determined. Herein, the threshold T0 refers to a leading end skewing amount making the medium S excessively oblique and traveling difficult. Under a condition in which the threshold T0 is exceeded, the transport operation of the medium S is stopped, and a “skew abnormality” is displayed on a display unit 151 of the control device 150.

In a case where the leading end skewing amount of the medium S is equal to or smaller than the threshold T0, the trailing end of the medium S passes through the position sensors 110 (111 and 112) when the trailing end passes through the reference line L. Accordingly, since the position sensors 110 (111 and 112) detect a skew of the trailing end of the medium S, a difference (skewing amount difference) between the leading end skewing amount and the trailing end skewing amount of the medium S is calculated, and whether or not the skewing amount difference is equal to or smaller than a threshold ΔT determined in advance is determined.

Herein, under a condition in which the skewing amount difference is equal to or smaller than the threshold ΔT, a normal transport operation is performed, and on a condition in which the skewing amount difference exceeds the threshold ΔT, the medium S is treated as a medium with a paper wrinkle.

In this case, the threshold ΔT of the skewing amount difference refers to a case where timings at which the leading end and the trailing end of the medium S pass through the position sensors 110 (111 and 112) are different between a leading end side and a trailing end side. It may be determined that there is no paper wrinkle insofar as the difference amount is within a permissible value. However, the presence or absence of a “paper wrinkle” may be determined assuming a case where the difference amount exceeds a threshold which has a high probability of leading to the generation of a paper wrinkle.

In the present example, in a case where the transport stopping mode is selected, the transport operation of the medium S is stopped, and “there is a paper wrinkle” is displayed on the display unit 151 of the control device 150. On the other hand, in a case where it is assumed that the transport stopping mode is not selected, the transport continuation mode is performed, and a medium with a paper wrinkle is discharged to another medium discharge receiver (not shown).

Relationship between Position Sensor Output and Paper Wrinkle Determination (1) Normal Transport

As shown in FIG. 6A, in a case where it is assumed that a medium S1 (S) is normally transported, timings at which the leading end and the trailing end of the medium S1 pass through the position sensors 110 (111 and 112) are the same as shown in FIG. 7A, and based on the output pattern, it is determined that the medium S1 is normally transported.

(2) Oblique Transport

It is assumed that the oblique transport is generally a case of being excessively oblique and a case leading to the skew abnormality described above.

As shown in FIG. 6B, in a case where it is assumed that a medium S2 (S) is skewed and obliquely transported, timings at which the leading end and the trailing end of the medium S pass through the position sensors 110 (111 and 112) are shifted from each other by the same time Δt as shown in FIG. 7B, and based on the output pattern, it is determined that the medium S2 is obliquely transported.

(3) There Is Paper Wrinkle

As shown in FIG. 6C, in a case where it is assumed that there is a paper wrinkle NG on any of both sides in the width direction, which are close to the trailing end of a medium S3 (S), timings at which the leading end and the trailing end of the medium S pass through the position sensors 110 (111 and 112) are the same on the leading end side as shown in FIG. 7C, but the timings are shifted from each other on the trailing end side by the time Δt, and based on the output pattern, it is determined that there is the paper wrinkle NG in the medium S.

Although there is the paper wrinkle NG close to the trailing end of the medium S in the present example, even in a case where there is a paper wrinkle close to the leading end of the medium S, an output pattern having a shift in the time Δt on the leading end side is obtained, and it is determined that there is the paper wrinkle NG in the medium S.

Combination with Medium Type Determiner

Although processing of determining the presence or absence of a paper wrinkle with respect to all of the media S is performed in the present example, without being limited thereto, for example, as shown by an imaginary line in FIG. 3 , determination information of a medium type from a medium type determiner 160 may be taken in by the processor, and the presence or absence of a paper wrinkle may be determined only in a case of the thin medium S, such as thin paper.

Herein, the medium type determiner 160 may include a thickness detector that directly detects whether the medium S is thin paper or is thick paper other than the thin paper and a medium designator that has a usable medium type table prepared in the memory in the control device 150 and designates the medium S to be used from the medium type table, and take medium type information determined based on these types of information into the control device 150.

Exemplary Embodiment 2

FIG. 4B shows major portions of a medium transporting device according to exemplary embodiment 2.

In FIG. 4B, the medium transporting device 100 includes the position aligning roller 90 and the transport roller 91 f which are the same as in exemplary embodiment 1, but configurations of the position sensors 110 (three position sensors 111 to 113 in the present example) and processing of determining the presence or absence of a paper wrinkle based on detection outputs from the position sensors 110 are different. Components that are the same as in exemplary embodiment 1 will be assigned with the same reference signs as in exemplary embodiment 1, and detailed description thereof will be omitted herein.

As shown in FIGS. 3 and 4B, the position sensors 110 (111 to 113) are provided at a plurality of places (three places in the present example) of the reference line L along the width direction intersecting the transport direction of the medium S, immediately behind the position aligning roller 90 (the parts separated away from the position aligning roller 90 by m, in the present example). As in exemplary embodiment 1, the position sensors 110 (111 and 112) of the present example are divided and arranged close to both end portions in the width direction intersecting the transport direction of the medium S, and the width dimension w between the two including the position sensors 111 and 112 is set to be shorter than a width dimension of the medium S having a usable size. In addition, the position sensor 110 (specifically, 113) is provided to substantially correspond to a central portion of the medium S in the width direction between the position sensors 111 and 112 on both sides. For this reason, in the present example, it is possible to detect a timing at which the leading end or the trailing end of the medium S passing through the position aligning roller 90 passes through the three position sensors 110 (111 to 113).

Control System of Medium Transporting Device

In the present example, the control device 150 is a device that installs necessary programs such as the medium S position aligning operation program and a “program for determining the presence or absence of a paper wrinkle (see FIG. 8 )” in advance in the memory (not shown), takes, into the processor, detection information from the position sensors 110 (111 to 113) in a case where the medium S, which has passed through the position aligning roller 90, passes through the position sensors 110 (111 to 113) after performing the medium S position aligning operation (corresponding to the aligning (registration) operation by the position aligning roller 90), executes the “program for determining the presence or absence of a paper wrinkle”, and determines the presence or absence of a paper wrinkle of the medium S.

Medium Position Aligning Operation

As shown in FIG. 8 , the medium S position aligning operation by the position aligning roller (registration roller) 90 that is the same as in exemplary embodiment 1 is performed before determining the presence or absence of a paper wrinkle of the medium S.

Medium Transport Resuming Operation

In a case where the medium S position aligning operation described above is completed, a transport operation of the medium S of which a position is aligned is resumed by the position aligning roller 90.

Then, in a case where the leading end of the medium S passes through the reference line L, the leading end passes through the position sensors 110 (111 to 113).

Herein, similarly to exemplary embodiment 1, whether the leading end skewing amount is equal to or smaller than the threshold T0 determined in advance is determined, and the presence or absence of a skew abnormality is determined under a condition in which the leading end skewing amount exceeds the threshold T0.

In a case where the leading end skewing amount of the medium S is equal to or smaller than the threshold T0, the trailing end of the medium S passes through the position sensors 110 (111 to 113) when the trailing end passes through the reference line L. Accordingly, since the position sensors 110 (111 to 113) detect a skew of the trailing end of the medium S, whether or not the inclinations of the leading end and the trailing end of the medium S are uniform is determined based on the leading end skewing amount and the trailing end skewing amount of the medium S.

Herein, under a condition in which the inclinations of the leading end and the trailing end of the medium S are uniform, a normal transport operation is performed. On a condition in which the inclinations of the leading end and the trailing end of the medium S are not uniform, the medium S is treated as a medium with a paper wrinkle.

In the present example, in a case where the transport stopping mode is selected, the transport operation of the medium S is stopped, and “there is a paper wrinkle” is displayed on the display unit 151 of the control device 150. On the other hand, in a case where it is assumed that the transport stopping mode is not selected, the transport continuation mode is performed, and a medium with a paper wrinkle is discharged to another medium discharge receiver (not shown).

Relationship between Position Sensor Output and Paper Wrinkle Determination (1) Normal Transport

As shown in FIG. 9A, in a case where it is assumed that the medium S1 (S) is normally transported, timings at which the leading end and the trailing end of the medium S1 pass through the position sensors 110 (111 to 113) are the same as shown in FIG. 11A, and based on the output pattern, it is determined that the medium is normally transported.

(2) Oblique Transport

It is assumed that the oblique transport is generally a case of being excessively oblique and a case leading to the skew abnormality described above.

As shown in FIG. 9B, in a case where it is assumed that the medium S2 (S) is skewed and obliquely transported, timings at which the leading end and the trailing end of the medium S2 pass the position sensors 110 (111 to 113) are shifted from each other by the same time Δt as shown in FIG. 11B, and based on the output pattern, it is determined that the medium S2 is obliquely transported.

(3) There Is Paper Wrinkle

As shown in FIG. 9C, in a case where it is assumed that there is the paper wrinkle NG at a central portion close to the trailing end of the medium S3 (S) in the width direction, timings at which the leading end and the trailing end of the medium S pass through the position sensors 110 (111 to 113) are the same on the leading end side as shown in FIG. 11C, but the position sensor 113 is shifted to be earlier than the position sensors 111 and 112 by the time Δt on the trailing end side, and based on the output pattern, it is determined that there is a paper wrinkle in the medium S3.

In addition, in the present example, since the position sensors 110 (111 to 113) are divided and arranged at three places including both side portions of the medium S in the width direction and the central portion in the width direction, even in a case where the paper wrinkle NG is arranged at any of both side portions in the width direction, which are close to the trailing end of the medium S, as shown in FIG. 10A, the position sensor 112 is shifted to be earlier than the position sensors 111 and 113 by the time Δt on the trailing end side as shown in FIG. 11D, and based on the output pattern, it is determined that there is a paper wrinkle in the medium S.

As described above, in the present exemplary embodiment, even in a case where the paper wrinkle NG is arranged at any of both side portions in the width direction, which are close to the trailing end of the medium S, or the central portion in the width direction as shown in FIGS. 10A and 10B, it is determined that there is the paper wrinkle NG in any case. In this regard, in exemplary embodiment 1, since the two position sensors 110 (111 and 112) tend to be difficult to detect a shift in the time Δt in a case where the paper wrinkle NG is arranged near the central portion in the width direction close to the trailing end of the medium S, for example, the present exemplary embodiment is preferable in that the determining accuracy of the paper wrinkle NG is high compared to exemplary embodiment 1.

Although there is the paper wrinkle NG close to the trailing end of the medium S in the present example, even in a case where there is a paper wrinkle close to the leading end of the medium S, an output pattern having a shift in the time Δt on the leading end side is obtained, and it is determined that there is the paper wrinkle NG in the medium S.

In addition, even in the present exemplary embodiment, as in exemplary embodiment 1, medium type information from the medium type determiner 160 may be taken into the control device 150, and processing of determining the presence or absence of a paper wrinkle may be performed only for the thin medium S such as thin paper.

Further, in a case where more than three position sensors 110 are provided, it is also possible to further improve the determining accuracy of the paper wrinkle NG.

The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. 

What is claimed is:
 1. A medium transporting device comprising: a positioning and transporting section that transports a medium after positioning a leading end position of the medium; an upstream transporting section that is provided on an upstream side of the positioning and transporting section in a medium transport direction and transports the medium toward the positioning and transporting section; a plurality of detection sections that are provided on a downstream side of the positioning and transporting section in the medium transport direction and detect, at a plurality of places of a reference line intersecting the transport direction of the medium, a timing at which a leading end or a trailing end of the medium passing through the positioning and transporting section passes; and a determination section that determines presence or absence of a wrinkle of the medium using detection results of the plurality of detection sections.
 2. A medium transporting device comprising: a positioning and transporting section that transports a medium after positioning a leading end position of the medium; an upstream transporting section that is provided on an upstream side of the positioning and transporting section in a medium transport direction and transports the medium toward the positioning and transporting section; a plurality of detection sections that are provided on a downstream side of the positioning and transporting section in the medium transport direction and detect, at a plurality of places of a reference line intersecting the transport direction of the medium, a timing at which a leading end or a trailing end of the medium passing through the positioning and transporting section passes; and a determination section that determines an oblique state of the leading end in the transport direction of the medium and presence or absence of a wrinkle of the medium using detection results of the plurality of detection sections.
 3. The medium transporting device according to claim 1, wherein the plurality of detection sections share a detection section that detects an oblique state of the leading end in the transport direction of the medium.
 4. The medium transporting device according to claim 2, wherein the plurality of detection sections share a detection section that detects an oblique state of the leading end in the transport direction of the medium.
 5. The medium transporting device according to claim 1, wherein the plurality of detection sections are provided immediately behind the positioning and transporting section.
 6. The medium transporting device according to claim 2, wherein the plurality of detection sections are provided immediately behind the positioning and transporting section.
 7. The medium transporting device according to claim 5, wherein all or some of the plurality of detection sections are divided and arranged close to both end portions in a width direction intersecting the transport direction of the medium. 6,
 8. The medium transporting device according to claim 6, wherein all or some of the plurality of detection sections are divided and arranged close to both end portions in a width direction intersecting the transport direction of the medium.
 9. The medium transporting device according to claim 1, wherein the plurality of detection sections are two detection sections and detect timings at which the leading end and the trailing end in the transport direction of the medium pass.
 10. The medium transporting device according to claim 2, wherein the plurality of detection sections are two detection sections and detect timings at which the leading end and the trailing end in the transport direction of the medium pass.
 11. The medium transporting device according to claim 9, wherein the determination section determines that there is the wrinkle in the medium on a condition in which inclination amount differences of the leading end and the trailing end in the transport direction of the medium with respect to the reference line are larger than a threshold determined in advance.
 12. The medium transporting device according to claim 10, wherein the determination section determines that there is the wrinkle in the medium on a condition in which inclination amount differences of the leading end and the trailing end in the transport direction of the medium with respect to the reference line are larger than a threshold determined in advance.
 13. The medium transporting device according to claim 1, wherein the plurality of detection sections are three or more detection sections and detect timings at which the leading end and the trailing end in the transport direction of the medium pass.
 14. The medium transporting device according to claim 2, wherein the plurality of detection sections are three or more detection sections and detect timings at which the leading end and the trailing end in the transport direction of the medium pass.
 15. The medium transporting device according to claim 13, wherein the determination section determines that there is the wrinkle in the medium on a condition in which an inclination amount of the leading end or the trailing end in the transport direction of the medium with respect to the reference line is not uniform in the width direction of the medium.
 16. The medium transporting device according to claim 1, wherein the determination section determines that a transport posture of the medium is excessively oblique on a condition in which an oblique state of the leading end in the transport direction of the medium exceeds a threshold determined in advance and determines the presence or absence of the wrinkle of the medium under a condition in which the oblique state is equal to or smaller than the threshold.
 17. The medium transporting device according to claim 16, wherein the determination section determines the presence or absence of the wrinkle of the medium in a case where the medium is a thin medium having a thickness determined in advance or smaller.
 18. The medium transporting device according to claim 1, further comprising: a removal processing section that performs, in a case where the determination section determines that there is the wrinkle in the medium, removal processing for removing the medium with the wrinkle from a transport path.
 19. The medium transporting device according to claim 18, further comprising: a notification section that issues a notification indicating that the medium has the wrinkle in a case where the determination section determines that there is the wrinkle in the medium.
 20. A medium processing apparatus comprising: the medium transporting device according to claim 1; and a processing section that performs processing determined in advance on the medium transported by the medium transporting device. 